Are neighbors pillaging nests: detecting spatial complexity of allopaternal care in the imperiled Egg-mimic Darter (Percidae: Etheostoma pseudovulatum)

Github link

http://ndisotell.github.io/E-pseudo

Abstract

Alloparental care behavior has been documented in several clades of animals, including fishes. Despite the increased energy cost of caring for more offspring, this behavior of raising non-descendent young also has potential benefits, including attraction of mates or reduced egg predation by dilution effects. The Egg-mimic Darter, Etheostoma pseudovulatum, is an imperiled darter species restricted to only five tributaries of the Duck river where they occur in rocky pools of small to medium-sized streams. Male Egg-mimic Darters and those of other species of clade Goneaperca construct nests under rocks and guard eggs until hatched. Two species from this clade, E. virgatum and E. olmstedi, exhibit allopaternal care; whether this is a common strategy to all members of the clade is not known. Furthermore, the potential benefits of kin-selection and how nest density or male size influences such behaviors have not been tested.

We will use microsatellite loci to obtain genotypes from the eggs, collected at the same locality from 2015 and 2019, of 17 and 21 nests respectively. Other non-guarding males and females from both collection events have also been captured to identify the following: (1) if allopaternal care occurs in this species, (2) if kin-selection is one benefit of allopaternal care, (3) if male size correlates to the proportion of non-descendant eggs in a nest, and (4) if distance between nests influences allopaternal care frequency.

To date, eggs from 38 nests, the guarding male for each, and 19 other non-guarding males have been collected from both years. DNA was extracted from non-target individuals from a second location and used as a template to optimize primers for 18 microsatellite loci that were variable within the focal taxon. The preliminary genotypic data has been generated for 4 of the 18 loci of the focal individuals from the year 2019 and subjected to parentage analyses using COLONY (V2.0) to address our objectives.

Photos of Mill creek site

The bridge showing the most downstream portion of the site.

A photo showing the most upstream portion of site

Videos of behavior

Map of Mill Creek

Natural History Information

Firstt, a boxplot of male total lengths from both years. Comparing the two the average means are still in fact close together.

Now, a comparison of the average number of clutches in a nest compared by collection year.

## [1] "Var1" "Var2" "Freq"

##   Year ClutchSize Total_number
## 1 2015          1           13
## 2 2019          1           20
## 3 2015          2           15
## 4 2019          2            3
## 5 2015          3            1
## 6 2019          3            0

Now for some summary tables to give a different depiction.

## # A tibble: 2 x 2
##   Year  meanMaleTL
##   <chr>      <dbl>
## 1 2015        75.2
## 2 2019        74.6

Table 2. A summary kable displaying number, mean, and standard deviation for both years.

Year	nMaleTL	meanMaleTL	sdMaleTL
2015	36	75.22222	5.990998
2019	23	74.56522	5.177101

Table 2. A summary kable displaying number, mean, and standard deviation for clutch size by year.

Year	n	meanClutchSize	sdClutchSize
2015	29	1.586207	0.5680318
2019	23	1.130435	0.3443502

And for funsies I ran an anova to try and see if there was any noticable correlation between t he size of the male and how many eggs were in the guarded nest.

## Analysis of Variance Table
## 
## Response: TotalEggs
##           Df Sum Sq Mean Sq F value Pr(>F)
## MaleSize   1  90113   90113  2.3079 0.1444
## Residuals 20 780902   39045

Preliminary Results

For Nest 5 clutch A here is a figure depicting the number of mismatched loci as compared to the present guarding and non guarding males. Males 26-01 and 10-02 appear to be the probable father for this first clutch. However, the known guarding male was M14-01.

Clutch A

Here in the second figure for Nest 5 clutch B we see that the known guarding male, M14-01, falls closer to the lower portion of the plot making it’s likelihood of being that particular parent higher than we saw in Clutch A. With more loci and more information there is a high likelihood of resolution that the first clutch is not the guarding males but the second is more genetically related.

Clutch B

References

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